The Evolution of Lice-Loving Bacteria

The way bacteria spread has changed a lot over time. Some bacteria have moved from ticks to lice. This switch often makes the bacteria more dangerous. Why and when this happened is a mystery. This is a story about one such bacteria, Borrelia recurrentis. A team of researchers dug up some old bacteria. These bacteria were buried for a long time. They were found in remains from 2300 to 600 years ago. The team studied these ancient bacteria. They found out some interesting things. The bacteria, Borrelia recurrentis, causes a disease called relapsing fever. It is spread by lice. The team compared this bacteria to its tick-loving cousin. They found out that the switch happened between 6000 to 4000 years ago. This was around the time people started using wool for clothes. This change in lifestyle might have helped the bacteria make the switch. The team also looked at the genes of the bacteria. They found out that most of the changes happened around 2300 years ago. But some changes kept happening until about 1000 years ago. These changes were mostly in the parts of the bacteria's DNA that help it spread. This study gives a clear picture of how this bacteria changed over time. It shows how the bacteria adapted to its new home in lice. It also shows how human lifestyle changes can affect the spread of diseases. This is not just about the past. It helps us understand how diseases might change in the future. It's a reminder that the world of bacteria is always changing. And so are the diseases they cause.